xref: /freebsd/sys/rpc/clnt_dg.c (revision 884a2a699669ec61e2366e3e358342dbc94be24a)
1 /*	$NetBSD: clnt_dg.c,v 1.4 2000/07/14 08:40:41 fvdl Exp $	*/
2 
3 /*
4  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
5  * unrestricted use provided that this legend is included on all tape
6  * media and as a part of the software program in whole or part.  Users
7  * may copy or modify Sun RPC without charge, but are not authorized
8  * to license or distribute it to anyone else except as part of a product or
9  * program developed by the user.
10  *
11  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
12  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
13  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
14  *
15  * Sun RPC is provided with no support and without any obligation on the
16  * part of Sun Microsystems, Inc. to assist in its use, correction,
17  * modification or enhancement.
18  *
19  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
20  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
21  * OR ANY PART THEREOF.
22  *
23  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
24  * or profits or other special, indirect and consequential damages, even if
25  * Sun has been advised of the possibility of such damages.
26  *
27  * Sun Microsystems, Inc.
28  * 2550 Garcia Avenue
29  * Mountain View, California  94043
30  */
31 /*
32  * Copyright (c) 1986-1991 by Sun Microsystems Inc.
33  */
34 
35 #if defined(LIBC_SCCS) && !defined(lint)
36 #ident	"@(#)clnt_dg.c	1.23	94/04/22 SMI"
37 static char sccsid[] = "@(#)clnt_dg.c 1.19 89/03/16 Copyr 1988 Sun Micro";
38 #endif
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41 
42 /*
43  * Implements a connectionless client side RPC.
44  */
45 
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/kernel.h>
49 #include <sys/lock.h>
50 #include <sys/malloc.h>
51 #include <sys/mbuf.h>
52 #include <sys/mutex.h>
53 #include <sys/pcpu.h>
54 #include <sys/proc.h>
55 #include <sys/socket.h>
56 #include <sys/socketvar.h>
57 #include <sys/time.h>
58 #include <sys/uio.h>
59 
60 #include <net/vnet.h>
61 
62 #include <rpc/rpc.h>
63 #include <rpc/rpc_com.h>
64 
65 
66 #ifdef _FREEFALL_CONFIG
67 /*
68  * Disable RPC exponential back-off for FreeBSD.org systems.
69  */
70 #define	RPC_MAX_BACKOFF		1 /* second */
71 #else
72 #define	RPC_MAX_BACKOFF		30 /* seconds */
73 #endif
74 
75 static bool_t time_not_ok(struct timeval *);
76 static enum clnt_stat clnt_dg_call(CLIENT *, struct rpc_callextra *,
77     rpcproc_t, struct mbuf *, struct mbuf **, struct timeval);
78 static void clnt_dg_geterr(CLIENT *, struct rpc_err *);
79 static bool_t clnt_dg_freeres(CLIENT *, xdrproc_t, void *);
80 static void clnt_dg_abort(CLIENT *);
81 static bool_t clnt_dg_control(CLIENT *, u_int, void *);
82 static void clnt_dg_close(CLIENT *);
83 static void clnt_dg_destroy(CLIENT *);
84 static int clnt_dg_soupcall(struct socket *so, void *arg, int waitflag);
85 
86 static struct clnt_ops clnt_dg_ops = {
87 	.cl_call =	clnt_dg_call,
88 	.cl_abort =	clnt_dg_abort,
89 	.cl_geterr =	clnt_dg_geterr,
90 	.cl_freeres =	clnt_dg_freeres,
91 	.cl_close =	clnt_dg_close,
92 	.cl_destroy =	clnt_dg_destroy,
93 	.cl_control =	clnt_dg_control
94 };
95 
96 static const char mem_err_clnt_dg[] = "clnt_dg_create: out of memory";
97 
98 /*
99  * A pending RPC request which awaits a reply. Requests which have
100  * received their reply will have cr_xid set to zero and cr_mrep to
101  * the mbuf chain of the reply.
102  */
103 struct cu_request {
104 	TAILQ_ENTRY(cu_request) cr_link;
105 	CLIENT			*cr_client;	/* owner */
106 	uint32_t		cr_xid;		/* XID of request */
107 	struct mbuf		*cr_mrep;	/* reply received by upcall */
108 	int			cr_error;	/* any error from upcall */
109 	char			cr_verf[MAX_AUTH_BYTES]; /* reply verf */
110 };
111 
112 TAILQ_HEAD(cu_request_list, cu_request);
113 
114 #define MCALL_MSG_SIZE 24
115 
116 /*
117  * This structure is pointed to by the socket buffer's sb_upcallarg
118  * member. It is separate from the client private data to facilitate
119  * multiple clients sharing the same socket. The cs_lock mutex is used
120  * to protect all fields of this structure, the socket's receive
121  * buffer SOCKBUF_LOCK is used to ensure that exactly one of these
122  * structures is installed on the socket.
123  */
124 struct cu_socket {
125 	struct mtx		cs_lock;
126 	int			cs_refs;	/* Count of clients */
127 	struct cu_request_list	cs_pending;	/* Requests awaiting replies */
128 	int			cs_upcallrefs;	/* Refcnt of upcalls in prog.*/
129 };
130 
131 static void clnt_dg_upcallsdone(struct socket *, struct cu_socket *);
132 
133 /*
134  * Private data kept per client handle
135  */
136 struct cu_data {
137 	int			cu_threads;	/* # threads in clnt_vc_call */
138 	bool_t			cu_closing;	/* TRUE if we are closing */
139 	bool_t			cu_closed;	/* TRUE if we are closed */
140 	struct socket		*cu_socket;	/* connection socket */
141 	bool_t			cu_closeit;	/* opened by library */
142 	struct sockaddr_storage	cu_raddr;	/* remote address */
143 	int			cu_rlen;
144 	struct timeval		cu_wait;	/* retransmit interval */
145 	struct timeval		cu_total;	/* total time for the call */
146 	struct rpc_err		cu_error;
147 	uint32_t		cu_xid;
148 	char			cu_mcallc[MCALL_MSG_SIZE]; /* marshalled callmsg */
149 	size_t			cu_mcalllen;
150 	size_t			cu_sendsz;	/* send size */
151 	size_t			cu_recvsz;	/* recv size */
152 	int			cu_async;
153 	int			cu_connect;	/* Use connect(). */
154 	int			cu_connected;	/* Have done connect(). */
155 	const char		*cu_waitchan;
156 	int			cu_waitflag;
157 	int			cu_cwnd;	/* congestion window */
158 	int			cu_sent;	/* number of in-flight RPCs */
159 	bool_t			cu_cwnd_wait;
160 };
161 
162 #define CWNDSCALE	256
163 #define MAXCWND		(32 * CWNDSCALE)
164 
165 /*
166  * Connection less client creation returns with client handle parameters.
167  * Default options are set, which the user can change using clnt_control().
168  * fd should be open and bound.
169  * NB: The rpch->cl_auth is initialized to null authentication.
170  * 	Caller may wish to set this something more useful.
171  *
172  * sendsz and recvsz are the maximum allowable packet sizes that can be
173  * sent and received. Normally they are the same, but they can be
174  * changed to improve the program efficiency and buffer allocation.
175  * If they are 0, use the transport default.
176  *
177  * If svcaddr is NULL, returns NULL.
178  */
179 CLIENT *
180 clnt_dg_create(
181 	struct socket *so,
182 	struct sockaddr *svcaddr,	/* servers address */
183 	rpcprog_t program,		/* program number */
184 	rpcvers_t version,		/* version number */
185 	size_t sendsz,			/* buffer recv size */
186 	size_t recvsz)			/* buffer send size */
187 {
188 	CLIENT *cl = NULL;		/* client handle */
189 	struct cu_data *cu = NULL;	/* private data */
190 	struct cu_socket *cs = NULL;
191 	struct sockbuf *sb;
192 	struct timeval now;
193 	struct rpc_msg call_msg;
194 	struct __rpc_sockinfo si;
195 	XDR xdrs;
196 	int error;
197 
198 	if (svcaddr == NULL) {
199 		rpc_createerr.cf_stat = RPC_UNKNOWNADDR;
200 		return (NULL);
201 	}
202 
203 	if (!__rpc_socket2sockinfo(so, &si)) {
204 		rpc_createerr.cf_stat = RPC_TLIERROR;
205 		rpc_createerr.cf_error.re_errno = 0;
206 		return (NULL);
207 	}
208 
209 	/*
210 	 * Find the receive and the send size
211 	 */
212 	sendsz = __rpc_get_t_size(si.si_af, si.si_proto, (int)sendsz);
213 	recvsz = __rpc_get_t_size(si.si_af, si.si_proto, (int)recvsz);
214 	if ((sendsz == 0) || (recvsz == 0)) {
215 		rpc_createerr.cf_stat = RPC_TLIERROR; /* XXX */
216 		rpc_createerr.cf_error.re_errno = 0;
217 		return (NULL);
218 	}
219 
220 	cl = mem_alloc(sizeof (CLIENT));
221 
222 	/*
223 	 * Should be multiple of 4 for XDR.
224 	 */
225 	sendsz = ((sendsz + 3) / 4) * 4;
226 	recvsz = ((recvsz + 3) / 4) * 4;
227 	cu = mem_alloc(sizeof (*cu));
228 	cu->cu_threads = 0;
229 	cu->cu_closing = FALSE;
230 	cu->cu_closed = FALSE;
231 	(void) memcpy(&cu->cu_raddr, svcaddr, (size_t)svcaddr->sa_len);
232 	cu->cu_rlen = svcaddr->sa_len;
233 	/* Other values can also be set through clnt_control() */
234 	cu->cu_wait.tv_sec = 3;	/* heuristically chosen */
235 	cu->cu_wait.tv_usec = 0;
236 	cu->cu_total.tv_sec = -1;
237 	cu->cu_total.tv_usec = -1;
238 	cu->cu_sendsz = sendsz;
239 	cu->cu_recvsz = recvsz;
240 	cu->cu_async = FALSE;
241 	cu->cu_connect = FALSE;
242 	cu->cu_connected = FALSE;
243 	cu->cu_waitchan = "rpcrecv";
244 	cu->cu_waitflag = 0;
245 	cu->cu_cwnd = MAXCWND / 2;
246 	cu->cu_sent = 0;
247 	cu->cu_cwnd_wait = FALSE;
248 	(void) getmicrotime(&now);
249 	cu->cu_xid = __RPC_GETXID(&now);
250 	call_msg.rm_xid = cu->cu_xid;
251 	call_msg.rm_call.cb_prog = program;
252 	call_msg.rm_call.cb_vers = version;
253 	xdrmem_create(&xdrs, cu->cu_mcallc, MCALL_MSG_SIZE, XDR_ENCODE);
254 	if (! xdr_callhdr(&xdrs, &call_msg)) {
255 		rpc_createerr.cf_stat = RPC_CANTENCODEARGS;  /* XXX */
256 		rpc_createerr.cf_error.re_errno = 0;
257 		goto err2;
258 	}
259 	cu->cu_mcalllen = XDR_GETPOS(&xdrs);
260 
261 	/*
262 	 * By default, closeit is always FALSE. It is users responsibility
263 	 * to do a close on it, else the user may use clnt_control
264 	 * to let clnt_destroy do it for him/her.
265 	 */
266 	cu->cu_closeit = FALSE;
267 	cu->cu_socket = so;
268 	error = soreserve(so, (u_long)sendsz, (u_long)recvsz);
269 	if (error != 0) {
270 		rpc_createerr.cf_stat = RPC_FAILED;
271 		rpc_createerr.cf_error.re_errno = error;
272 		goto err2;
273 	}
274 
275 	sb = &so->so_rcv;
276 	SOCKBUF_LOCK(&so->so_rcv);
277 recheck_socket:
278 	if (sb->sb_upcall) {
279 		if (sb->sb_upcall != clnt_dg_soupcall) {
280 			SOCKBUF_UNLOCK(&so->so_rcv);
281 			printf("clnt_dg_create(): socket already has an incompatible upcall\n");
282 			goto err2;
283 		}
284 		cs = (struct cu_socket *) sb->sb_upcallarg;
285 		mtx_lock(&cs->cs_lock);
286 		cs->cs_refs++;
287 		mtx_unlock(&cs->cs_lock);
288 	} else {
289 		/*
290 		 * We are the first on this socket - allocate the
291 		 * structure and install it in the socket.
292 		 */
293 		SOCKBUF_UNLOCK(&so->so_rcv);
294 		cs = mem_alloc(sizeof(*cs));
295 		SOCKBUF_LOCK(&so->so_rcv);
296 		if (sb->sb_upcall) {
297 			/*
298 			 * We have lost a race with some other client.
299 			 */
300 			mem_free(cs, sizeof(*cs));
301 			goto recheck_socket;
302 		}
303 		mtx_init(&cs->cs_lock, "cs->cs_lock", NULL, MTX_DEF);
304 		cs->cs_refs = 1;
305 		cs->cs_upcallrefs = 0;
306 		TAILQ_INIT(&cs->cs_pending);
307 		soupcall_set(so, SO_RCV, clnt_dg_soupcall, cs);
308 	}
309 	SOCKBUF_UNLOCK(&so->so_rcv);
310 
311 	cl->cl_refs = 1;
312 	cl->cl_ops = &clnt_dg_ops;
313 	cl->cl_private = (caddr_t)(void *)cu;
314 	cl->cl_auth = authnone_create();
315 	cl->cl_tp = NULL;
316 	cl->cl_netid = NULL;
317 	return (cl);
318 err2:
319 	if (cl) {
320 		mem_free(cl, sizeof (CLIENT));
321 		if (cu)
322 			mem_free(cu, sizeof (*cu));
323 	}
324 	return (NULL);
325 }
326 
327 static enum clnt_stat
328 clnt_dg_call(
329 	CLIENT		*cl,		/* client handle */
330 	struct rpc_callextra *ext,	/* call metadata */
331 	rpcproc_t	proc,		/* procedure number */
332 	struct mbuf	*args,		/* pointer to args */
333 	struct mbuf	**resultsp,	/* pointer to results */
334 	struct timeval	utimeout)	/* seconds to wait before giving up */
335 {
336 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
337 	struct cu_socket *cs;
338 	struct rpc_timers *rt;
339 	AUTH *auth;
340 	struct rpc_err *errp;
341 	enum clnt_stat stat;
342 	XDR xdrs;
343 	struct rpc_msg reply_msg;
344 	bool_t ok;
345 	int retrans;			/* number of re-transmits so far */
346 	int nrefreshes = 2;		/* number of times to refresh cred */
347 	struct timeval *tvp;
348 	int timeout;
349 	int retransmit_time;
350 	int next_sendtime, starttime, rtt, time_waited, tv = 0;
351 	struct sockaddr *sa;
352 	socklen_t salen;
353 	uint32_t xid = 0;
354 	struct mbuf *mreq = NULL, *results;
355 	struct cu_request *cr;
356 	int error;
357 
358 	cs = cu->cu_socket->so_rcv.sb_upcallarg;
359 	cr = malloc(sizeof(struct cu_request), M_RPC, M_WAITOK);
360 
361 	mtx_lock(&cs->cs_lock);
362 
363 	if (cu->cu_closing || cu->cu_closed) {
364 		mtx_unlock(&cs->cs_lock);
365 		free(cr, M_RPC);
366 		return (RPC_CANTSEND);
367 	}
368 	cu->cu_threads++;
369 
370 	if (ext) {
371 		auth = ext->rc_auth;
372 		errp = &ext->rc_err;
373 	} else {
374 		auth = cl->cl_auth;
375 		errp = &cu->cu_error;
376 	}
377 
378 	cr->cr_client = cl;
379 	cr->cr_mrep = NULL;
380 	cr->cr_error = 0;
381 
382 	if (cu->cu_total.tv_usec == -1) {
383 		tvp = &utimeout; /* use supplied timeout */
384 	} else {
385 		tvp = &cu->cu_total; /* use default timeout */
386 	}
387 	if (tvp->tv_sec || tvp->tv_usec)
388 		timeout = tvtohz(tvp);
389 	else
390 		timeout = 0;
391 
392 	if (cu->cu_connect && !cu->cu_connected) {
393 		mtx_unlock(&cs->cs_lock);
394 		error = soconnect(cu->cu_socket,
395 		    (struct sockaddr *)&cu->cu_raddr, curthread);
396 		mtx_lock(&cs->cs_lock);
397 		if (error) {
398 			errp->re_errno = error;
399 			errp->re_status = stat = RPC_CANTSEND;
400 			goto out;
401 		}
402 		cu->cu_connected = 1;
403 	}
404 	if (cu->cu_connected) {
405 		sa = NULL;
406 		salen = 0;
407 	} else {
408 		sa = (struct sockaddr *)&cu->cu_raddr;
409 		salen = cu->cu_rlen;
410 	}
411 	time_waited = 0;
412 	retrans = 0;
413 	if (ext && ext->rc_timers) {
414 		rt = ext->rc_timers;
415 		if (!rt->rt_rtxcur)
416 			rt->rt_rtxcur = tvtohz(&cu->cu_wait);
417 		retransmit_time = next_sendtime = rt->rt_rtxcur;
418 	} else {
419 		rt = NULL;
420 		retransmit_time = next_sendtime = tvtohz(&cu->cu_wait);
421 	}
422 
423 	starttime = ticks;
424 
425 call_again:
426 	mtx_assert(&cs->cs_lock, MA_OWNED);
427 
428 	cu->cu_xid++;
429 	xid = cu->cu_xid;
430 
431 send_again:
432 	mtx_unlock(&cs->cs_lock);
433 
434 	MGETHDR(mreq, M_WAIT, MT_DATA);
435 	KASSERT(cu->cu_mcalllen <= MHLEN, ("RPC header too big"));
436 	bcopy(cu->cu_mcallc, mreq->m_data, cu->cu_mcalllen);
437 	mreq->m_len = cu->cu_mcalllen;
438 
439 	/*
440 	 * The XID is the first thing in the request.
441 	 */
442 	*mtod(mreq, uint32_t *) = htonl(xid);
443 
444 	xdrmbuf_create(&xdrs, mreq, XDR_ENCODE);
445 
446 	if (cu->cu_async == TRUE && args == NULL)
447 		goto get_reply;
448 
449 	if ((! XDR_PUTINT32(&xdrs, &proc)) ||
450 	    (! AUTH_MARSHALL(auth, xid, &xdrs,
451 		m_copym(args, 0, M_COPYALL, M_WAITOK)))) {
452 		errp->re_status = stat = RPC_CANTENCODEARGS;
453 		mtx_lock(&cs->cs_lock);
454 		goto out;
455 	}
456 	mreq->m_pkthdr.len = m_length(mreq, NULL);
457 
458 	cr->cr_xid = xid;
459 	mtx_lock(&cs->cs_lock);
460 
461 	/*
462 	 * Try to get a place in the congestion window.
463 	 */
464 	while (cu->cu_sent >= cu->cu_cwnd) {
465 		cu->cu_cwnd_wait = TRUE;
466 		error = msleep(&cu->cu_cwnd_wait, &cs->cs_lock,
467 		    cu->cu_waitflag, "rpccwnd", 0);
468 		if (error) {
469 			errp->re_errno = error;
470 			errp->re_status = stat = RPC_CANTSEND;
471 			goto out;
472 		}
473 	}
474 	cu->cu_sent += CWNDSCALE;
475 
476 	TAILQ_INSERT_TAIL(&cs->cs_pending, cr, cr_link);
477 	mtx_unlock(&cs->cs_lock);
478 
479 	/*
480 	 * sosend consumes mreq.
481 	 */
482 	error = sosend(cu->cu_socket, sa, NULL, mreq, NULL, 0, curthread);
483 	mreq = NULL;
484 
485 	/*
486 	 * sub-optimal code appears here because we have
487 	 * some clock time to spare while the packets are in flight.
488 	 * (We assume that this is actually only executed once.)
489 	 */
490 	reply_msg.acpted_rply.ar_verf.oa_flavor = AUTH_NULL;
491 	reply_msg.acpted_rply.ar_verf.oa_base = cr->cr_verf;
492 	reply_msg.acpted_rply.ar_verf.oa_length = 0;
493 	reply_msg.acpted_rply.ar_results.where = NULL;
494 	reply_msg.acpted_rply.ar_results.proc = (xdrproc_t)xdr_void;
495 
496 	mtx_lock(&cs->cs_lock);
497 	if (error) {
498 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
499 		errp->re_errno = error;
500 		errp->re_status = stat = RPC_CANTSEND;
501 		cu->cu_sent -= CWNDSCALE;
502 		if (cu->cu_cwnd_wait) {
503 			cu->cu_cwnd_wait = FALSE;
504 			wakeup(&cu->cu_cwnd_wait);
505 		}
506 		goto out;
507 	}
508 
509 	/*
510 	 * Check to see if we got an upcall while waiting for the
511 	 * lock.
512 	 */
513 	if (cr->cr_error) {
514 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
515 		errp->re_errno = cr->cr_error;
516 		errp->re_status = stat = RPC_CANTRECV;
517 		cu->cu_sent -= CWNDSCALE;
518 		if (cu->cu_cwnd_wait) {
519 			cu->cu_cwnd_wait = FALSE;
520 			wakeup(&cu->cu_cwnd_wait);
521 		}
522 		goto out;
523 	}
524 	if (cr->cr_mrep) {
525 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
526 		cu->cu_sent -= CWNDSCALE;
527 		if (cu->cu_cwnd_wait) {
528 			cu->cu_cwnd_wait = FALSE;
529 			wakeup(&cu->cu_cwnd_wait);
530 		}
531 		goto got_reply;
532 	}
533 
534 	/*
535 	 * Hack to provide rpc-based message passing
536 	 */
537 	if (timeout == 0) {
538 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
539 		errp->re_status = stat = RPC_TIMEDOUT;
540 		cu->cu_sent -= CWNDSCALE;
541 		if (cu->cu_cwnd_wait) {
542 			cu->cu_cwnd_wait = FALSE;
543 			wakeup(&cu->cu_cwnd_wait);
544 		}
545 		goto out;
546 	}
547 
548 get_reply:
549 	for (;;) {
550 		/* Decide how long to wait. */
551 		if (next_sendtime < timeout)
552 			tv = next_sendtime;
553 		else
554 			tv = timeout;
555 		tv -= time_waited;
556 
557 		if (tv > 0) {
558 			if (cu->cu_closing || cu->cu_closed) {
559 				error = 0;
560 				cr->cr_error = ESHUTDOWN;
561 			} else {
562 				error = msleep(cr, &cs->cs_lock,
563 				    cu->cu_waitflag, cu->cu_waitchan, tv);
564 			}
565 		} else {
566 			error = EWOULDBLOCK;
567 		}
568 
569 		TAILQ_REMOVE(&cs->cs_pending, cr, cr_link);
570 		cu->cu_sent -= CWNDSCALE;
571 		if (cu->cu_cwnd_wait) {
572 			cu->cu_cwnd_wait = FALSE;
573 			wakeup(&cu->cu_cwnd_wait);
574 		}
575 
576 		if (!error) {
577 			/*
578 			 * We were woken up by the upcall.  If the
579 			 * upcall had a receive error, report that,
580 			 * otherwise we have a reply.
581 			 */
582 			if (cr->cr_error) {
583 				errp->re_errno = cr->cr_error;
584 				errp->re_status = stat = RPC_CANTRECV;
585 				goto out;
586 			}
587 
588 			cu->cu_cwnd += (CWNDSCALE * CWNDSCALE
589 			    + cu->cu_cwnd / 2) / cu->cu_cwnd;
590 			if (cu->cu_cwnd > MAXCWND)
591 				cu->cu_cwnd = MAXCWND;
592 
593 			if (rt) {
594 				/*
595 				 * Add one to the time since a tick
596 				 * count of N means that the actual
597 				 * time taken was somewhere between N
598 				 * and N+1.
599 				 */
600 				rtt = ticks - starttime + 1;
601 
602 				/*
603 				 * Update our estimate of the round
604 				 * trip time using roughly the
605 				 * algorithm described in RFC
606 				 * 2988. Given an RTT sample R:
607 				 *
608 				 * RTTVAR = (1-beta) * RTTVAR + beta * |SRTT-R|
609 				 * SRTT = (1-alpha) * SRTT + alpha * R
610 				 *
611 				 * where alpha = 0.125 and beta = 0.25.
612 				 *
613 				 * The initial retransmit timeout is
614 				 * SRTT + 4*RTTVAR and doubles on each
615 				 * retransmision.
616 				 */
617 				if (rt->rt_srtt == 0) {
618 					rt->rt_srtt = rtt;
619 					rt->rt_deviate = rtt / 2;
620 				} else {
621 					int32_t error = rtt - rt->rt_srtt;
622 					rt->rt_srtt += error / 8;
623 					error = abs(error) - rt->rt_deviate;
624 					rt->rt_deviate += error / 4;
625 				}
626 				rt->rt_rtxcur = rt->rt_srtt + 4*rt->rt_deviate;
627 			}
628 
629 			break;
630 		}
631 
632 		/*
633 		 * The sleep returned an error so our request is still
634 		 * on the list. If we got EWOULDBLOCK, we may want to
635 		 * re-send the request.
636 		 */
637 		if (error != EWOULDBLOCK) {
638 			errp->re_errno = error;
639 			if (error == EINTR)
640 				errp->re_status = stat = RPC_INTR;
641 			else
642 				errp->re_status = stat = RPC_CANTRECV;
643 			goto out;
644 		}
645 
646 		time_waited = ticks - starttime;
647 
648 		/* Check for timeout. */
649 		if (time_waited > timeout) {
650 			errp->re_errno = EWOULDBLOCK;
651 			errp->re_status = stat = RPC_TIMEDOUT;
652 			goto out;
653 		}
654 
655 		/* Retransmit if necessary. */
656 		if (time_waited >= next_sendtime) {
657 			cu->cu_cwnd /= 2;
658 			if (cu->cu_cwnd < CWNDSCALE)
659 				cu->cu_cwnd = CWNDSCALE;
660 			if (ext && ext->rc_feedback) {
661 				mtx_unlock(&cs->cs_lock);
662 				if (retrans == 0)
663 					ext->rc_feedback(FEEDBACK_REXMIT1,
664 					    proc, ext->rc_feedback_arg);
665 				else
666 					ext->rc_feedback(FEEDBACK_REXMIT2,
667 					    proc, ext->rc_feedback_arg);
668 				mtx_lock(&cs->cs_lock);
669 			}
670 			if (cu->cu_closing || cu->cu_closed) {
671 				errp->re_errno = ESHUTDOWN;
672 				errp->re_status = stat = RPC_CANTRECV;
673 				goto out;
674 			}
675 			retrans++;
676 			/* update retransmit_time */
677 			if (retransmit_time < RPC_MAX_BACKOFF * hz)
678 				retransmit_time = 2 * retransmit_time;
679 			next_sendtime += retransmit_time;
680 			goto send_again;
681 		}
682 		TAILQ_INSERT_TAIL(&cs->cs_pending, cr, cr_link);
683 	}
684 
685 got_reply:
686 	/*
687 	 * Now decode and validate the response. We need to drop the
688 	 * lock since xdr_replymsg may end up sleeping in malloc.
689 	 */
690 	mtx_unlock(&cs->cs_lock);
691 
692 	if (ext && ext->rc_feedback)
693 		ext->rc_feedback(FEEDBACK_OK, proc, ext->rc_feedback_arg);
694 
695 	xdrmbuf_create(&xdrs, cr->cr_mrep, XDR_DECODE);
696 	ok = xdr_replymsg(&xdrs, &reply_msg);
697 	cr->cr_mrep = NULL;
698 
699 	if (ok) {
700 		if ((reply_msg.rm_reply.rp_stat == MSG_ACCEPTED) &&
701 		    (reply_msg.acpted_rply.ar_stat == SUCCESS))
702 			errp->re_status = stat = RPC_SUCCESS;
703 		else
704 			stat = _seterr_reply(&reply_msg, &(cu->cu_error));
705 
706 		if (errp->re_status == RPC_SUCCESS) {
707 			results = xdrmbuf_getall(&xdrs);
708 			if (! AUTH_VALIDATE(auth, xid,
709 				&reply_msg.acpted_rply.ar_verf,
710 				&results)) {
711 				errp->re_status = stat = RPC_AUTHERROR;
712 				errp->re_why = AUTH_INVALIDRESP;
713 				if (retrans &&
714 				    auth->ah_cred.oa_flavor == RPCSEC_GSS) {
715 					/*
716 					 * If we retransmitted, its
717 					 * possible that we will
718 					 * receive a reply for one of
719 					 * the earlier transmissions
720 					 * (which will use an older
721 					 * RPCSEC_GSS sequence
722 					 * number). In this case, just
723 					 * go back and listen for a
724 					 * new reply. We could keep a
725 					 * record of all the seq
726 					 * numbers we have transmitted
727 					 * so far so that we could
728 					 * accept a reply for any of
729 					 * them here.
730 					 */
731 					XDR_DESTROY(&xdrs);
732 					mtx_lock(&cs->cs_lock);
733 					TAILQ_INSERT_TAIL(&cs->cs_pending,
734 					    cr, cr_link);
735 					cr->cr_mrep = NULL;
736 					goto get_reply;
737 				}
738 			} else {
739 				*resultsp = results;
740 			}
741 		}		/* end successful completion */
742 		/*
743 		 * If unsuccesful AND error is an authentication error
744 		 * then refresh credentials and try again, else break
745 		 */
746 		else if (stat == RPC_AUTHERROR)
747 			/* maybe our credentials need to be refreshed ... */
748 			if (nrefreshes > 0 &&
749 			    AUTH_REFRESH(auth, &reply_msg)) {
750 				nrefreshes--;
751 				XDR_DESTROY(&xdrs);
752 				mtx_lock(&cs->cs_lock);
753 				goto call_again;
754 			}
755 		/* end of unsuccessful completion */
756 	}	/* end of valid reply message */
757 	else {
758 		errp->re_status = stat = RPC_CANTDECODERES;
759 
760 	}
761 	XDR_DESTROY(&xdrs);
762 	mtx_lock(&cs->cs_lock);
763 out:
764 	mtx_assert(&cs->cs_lock, MA_OWNED);
765 
766 	if (mreq)
767 		m_freem(mreq);
768 	if (cr->cr_mrep)
769 		m_freem(cr->cr_mrep);
770 
771 	cu->cu_threads--;
772 	if (cu->cu_closing)
773 		wakeup(cu);
774 
775 	mtx_unlock(&cs->cs_lock);
776 
777 	if (auth && stat != RPC_SUCCESS)
778 		AUTH_VALIDATE(auth, xid, NULL, NULL);
779 
780 	free(cr, M_RPC);
781 
782 	return (stat);
783 }
784 
785 static void
786 clnt_dg_geterr(CLIENT *cl, struct rpc_err *errp)
787 {
788 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
789 
790 	*errp = cu->cu_error;
791 }
792 
793 static bool_t
794 clnt_dg_freeres(CLIENT *cl, xdrproc_t xdr_res, void *res_ptr)
795 {
796 	XDR xdrs;
797 	bool_t dummy;
798 
799 	xdrs.x_op = XDR_FREE;
800 	dummy = (*xdr_res)(&xdrs, res_ptr);
801 
802 	return (dummy);
803 }
804 
805 /*ARGSUSED*/
806 static void
807 clnt_dg_abort(CLIENT *h)
808 {
809 }
810 
811 static bool_t
812 clnt_dg_control(CLIENT *cl, u_int request, void *info)
813 {
814 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
815 	struct cu_socket *cs;
816 	struct sockaddr *addr;
817 
818 	cs = cu->cu_socket->so_rcv.sb_upcallarg;
819 	mtx_lock(&cs->cs_lock);
820 
821 	switch (request) {
822 	case CLSET_FD_CLOSE:
823 		cu->cu_closeit = TRUE;
824 		mtx_unlock(&cs->cs_lock);
825 		return (TRUE);
826 	case CLSET_FD_NCLOSE:
827 		cu->cu_closeit = FALSE;
828 		mtx_unlock(&cs->cs_lock);
829 		return (TRUE);
830 	}
831 
832 	/* for other requests which use info */
833 	if (info == NULL) {
834 		mtx_unlock(&cs->cs_lock);
835 		return (FALSE);
836 	}
837 	switch (request) {
838 	case CLSET_TIMEOUT:
839 		if (time_not_ok((struct timeval *)info)) {
840 			mtx_unlock(&cs->cs_lock);
841 			return (FALSE);
842 		}
843 		cu->cu_total = *(struct timeval *)info;
844 		break;
845 	case CLGET_TIMEOUT:
846 		*(struct timeval *)info = cu->cu_total;
847 		break;
848 	case CLSET_RETRY_TIMEOUT:
849 		if (time_not_ok((struct timeval *)info)) {
850 			mtx_unlock(&cs->cs_lock);
851 			return (FALSE);
852 		}
853 		cu->cu_wait = *(struct timeval *)info;
854 		break;
855 	case CLGET_RETRY_TIMEOUT:
856 		*(struct timeval *)info = cu->cu_wait;
857 		break;
858 	case CLGET_SVC_ADDR:
859 		/*
860 		 * Slightly different semantics to userland - we use
861 		 * sockaddr instead of netbuf.
862 		 */
863 		memcpy(info, &cu->cu_raddr, cu->cu_raddr.ss_len);
864 		break;
865 	case CLSET_SVC_ADDR:		/* set to new address */
866 		addr = (struct sockaddr *)info;
867 		(void) memcpy(&cu->cu_raddr, addr, addr->sa_len);
868 		break;
869 	case CLGET_XID:
870 		*(uint32_t *)info = cu->cu_xid;
871 		break;
872 
873 	case CLSET_XID:
874 		/* This will set the xid of the NEXT call */
875 		/* decrement by 1 as clnt_dg_call() increments once */
876 		cu->cu_xid = *(uint32_t *)info - 1;
877 		break;
878 
879 	case CLGET_VERS:
880 		/*
881 		 * This RELIES on the information that, in the call body,
882 		 * the version number field is the fifth field from the
883 		 * begining of the RPC header. MUST be changed if the
884 		 * call_struct is changed
885 		 */
886 		*(uint32_t *)info =
887 		    ntohl(*(uint32_t *)(void *)(cu->cu_mcallc +
888 		    4 * BYTES_PER_XDR_UNIT));
889 		break;
890 
891 	case CLSET_VERS:
892 		*(uint32_t *)(void *)(cu->cu_mcallc + 4 * BYTES_PER_XDR_UNIT)
893 			= htonl(*(uint32_t *)info);
894 		break;
895 
896 	case CLGET_PROG:
897 		/*
898 		 * This RELIES on the information that, in the call body,
899 		 * the program number field is the fourth field from the
900 		 * begining of the RPC header. MUST be changed if the
901 		 * call_struct is changed
902 		 */
903 		*(uint32_t *)info =
904 		    ntohl(*(uint32_t *)(void *)(cu->cu_mcallc +
905 		    3 * BYTES_PER_XDR_UNIT));
906 		break;
907 
908 	case CLSET_PROG:
909 		*(uint32_t *)(void *)(cu->cu_mcallc + 3 * BYTES_PER_XDR_UNIT)
910 			= htonl(*(uint32_t *)info);
911 		break;
912 	case CLSET_ASYNC:
913 		cu->cu_async = *(int *)info;
914 		break;
915 	case CLSET_CONNECT:
916 		cu->cu_connect = *(int *)info;
917 		break;
918 	case CLSET_WAITCHAN:
919 		cu->cu_waitchan = (const char *)info;
920 		break;
921 	case CLGET_WAITCHAN:
922 		*(const char **) info = cu->cu_waitchan;
923 		break;
924 	case CLSET_INTERRUPTIBLE:
925 		if (*(int *) info)
926 			cu->cu_waitflag = PCATCH;
927 		else
928 			cu->cu_waitflag = 0;
929 		break;
930 	case CLGET_INTERRUPTIBLE:
931 		if (cu->cu_waitflag)
932 			*(int *) info = TRUE;
933 		else
934 			*(int *) info = FALSE;
935 		break;
936 	default:
937 		mtx_unlock(&cs->cs_lock);
938 		return (FALSE);
939 	}
940 	mtx_unlock(&cs->cs_lock);
941 	return (TRUE);
942 }
943 
944 static void
945 clnt_dg_close(CLIENT *cl)
946 {
947 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
948 	struct cu_socket *cs;
949 	struct cu_request *cr;
950 
951 	cs = cu->cu_socket->so_rcv.sb_upcallarg;
952 	mtx_lock(&cs->cs_lock);
953 
954 	if (cu->cu_closed) {
955 		mtx_unlock(&cs->cs_lock);
956 		return;
957 	}
958 
959 	if (cu->cu_closing) {
960 		while (cu->cu_closing)
961 			msleep(cu, &cs->cs_lock, 0, "rpcclose", 0);
962 		KASSERT(cu->cu_closed, ("client should be closed"));
963 		mtx_unlock(&cs->cs_lock);
964 		return;
965 	}
966 
967 	/*
968 	 * Abort any pending requests and wait until everyone
969 	 * has finished with clnt_vc_call.
970 	 */
971 	cu->cu_closing = TRUE;
972 	TAILQ_FOREACH(cr, &cs->cs_pending, cr_link) {
973 		if (cr->cr_client == cl) {
974 			cr->cr_xid = 0;
975 			cr->cr_error = ESHUTDOWN;
976 			wakeup(cr);
977 		}
978 	}
979 
980 	while (cu->cu_threads)
981 		msleep(cu, &cs->cs_lock, 0, "rpcclose", 0);
982 
983 	cu->cu_closing = FALSE;
984 	cu->cu_closed = TRUE;
985 
986 	mtx_unlock(&cs->cs_lock);
987 	wakeup(cu);
988 }
989 
990 static void
991 clnt_dg_destroy(CLIENT *cl)
992 {
993 	struct cu_data *cu = (struct cu_data *)cl->cl_private;
994 	struct cu_socket *cs;
995 	struct socket *so = NULL;
996 	bool_t lastsocketref;
997 
998 	cs = cu->cu_socket->so_rcv.sb_upcallarg;
999 	clnt_dg_close(cl);
1000 
1001 	mtx_lock(&cs->cs_lock);
1002 
1003 	cs->cs_refs--;
1004 	if (cs->cs_refs == 0) {
1005 		mtx_unlock(&cs->cs_lock);
1006 		SOCKBUF_LOCK(&cu->cu_socket->so_rcv);
1007 		soupcall_clear(cu->cu_socket, SO_RCV);
1008 		clnt_dg_upcallsdone(cu->cu_socket, cs);
1009 		SOCKBUF_UNLOCK(&cu->cu_socket->so_rcv);
1010 		mtx_destroy(&cs->cs_lock);
1011 		mem_free(cs, sizeof(*cs));
1012 		lastsocketref = TRUE;
1013 	} else {
1014 		mtx_unlock(&cs->cs_lock);
1015 		lastsocketref = FALSE;
1016 	}
1017 
1018 	if (cu->cu_closeit && lastsocketref) {
1019 		so = cu->cu_socket;
1020 		cu->cu_socket = NULL;
1021 	}
1022 
1023 	if (so)
1024 		soclose(so);
1025 
1026 	if (cl->cl_netid && cl->cl_netid[0])
1027 		mem_free(cl->cl_netid, strlen(cl->cl_netid) +1);
1028 	if (cl->cl_tp && cl->cl_tp[0])
1029 		mem_free(cl->cl_tp, strlen(cl->cl_tp) +1);
1030 	mem_free(cu, sizeof (*cu));
1031 	mem_free(cl, sizeof (CLIENT));
1032 }
1033 
1034 /*
1035  * Make sure that the time is not garbage.  -1 value is allowed.
1036  */
1037 static bool_t
1038 time_not_ok(struct timeval *t)
1039 {
1040 	return (t->tv_sec < -1 || t->tv_sec > 100000000 ||
1041 		t->tv_usec < -1 || t->tv_usec > 1000000);
1042 }
1043 
1044 int
1045 clnt_dg_soupcall(struct socket *so, void *arg, int waitflag)
1046 {
1047 	struct cu_socket *cs = (struct cu_socket *) arg;
1048 	struct uio uio;
1049 	struct mbuf *m;
1050 	struct mbuf *control;
1051 	struct cu_request *cr;
1052 	int error, rcvflag, foundreq;
1053 	uint32_t xid;
1054 
1055 	cs->cs_upcallrefs++;
1056 	uio.uio_resid = 1000000000;
1057 	uio.uio_td = curthread;
1058 	do {
1059 		SOCKBUF_UNLOCK(&so->so_rcv);
1060 		m = NULL;
1061 		control = NULL;
1062 		rcvflag = MSG_DONTWAIT;
1063 		error = soreceive(so, NULL, &uio, &m, &control, &rcvflag);
1064 		if (control)
1065 			m_freem(control);
1066 		SOCKBUF_LOCK(&so->so_rcv);
1067 
1068 		if (error == EWOULDBLOCK)
1069 			break;
1070 
1071 		/*
1072 		 * If there was an error, wake up all pending
1073 		 * requests.
1074 		 */
1075 		if (error) {
1076 			mtx_lock(&cs->cs_lock);
1077 			TAILQ_FOREACH(cr, &cs->cs_pending, cr_link) {
1078 				cr->cr_xid = 0;
1079 				cr->cr_error = error;
1080 				wakeup(cr);
1081 			}
1082 			mtx_unlock(&cs->cs_lock);
1083 			break;
1084 		}
1085 
1086 		/*
1087 		 * The XID is in the first uint32_t of the reply.
1088 		 */
1089 		if (m->m_len < sizeof(xid) && m_length(m, NULL) < sizeof(xid)) {
1090 			/*
1091 			 * Should never happen.
1092 			 */
1093 			m_freem(m);
1094 			continue;
1095 		}
1096 
1097 		m_copydata(m, 0, sizeof(xid), (char *)&xid);
1098 		xid = ntohl(xid);
1099 
1100 		/*
1101 		 * Attempt to match this reply with a pending request.
1102 		 */
1103 		mtx_lock(&cs->cs_lock);
1104 		foundreq = 0;
1105 		TAILQ_FOREACH(cr, &cs->cs_pending, cr_link) {
1106 			if (cr->cr_xid == xid) {
1107 				/*
1108 				 * This one matches. We leave the
1109 				 * reply mbuf in cr->cr_mrep. Set the
1110 				 * XID to zero so that we will ignore
1111 				 * any duplicated replies that arrive
1112 				 * before clnt_dg_call removes it from
1113 				 * the queue.
1114 				 */
1115 				cr->cr_xid = 0;
1116 				cr->cr_mrep = m;
1117 				cr->cr_error = 0;
1118 				foundreq = 1;
1119 				wakeup(cr);
1120 				break;
1121 			}
1122 		}
1123 		mtx_unlock(&cs->cs_lock);
1124 
1125 		/*
1126 		 * If we didn't find the matching request, just drop
1127 		 * it - its probably a repeated reply.
1128 		 */
1129 		if (!foundreq)
1130 			m_freem(m);
1131 	} while (m);
1132 	cs->cs_upcallrefs--;
1133 	if (cs->cs_upcallrefs < 0)
1134 		panic("rpcdg upcall refcnt");
1135 	if (cs->cs_upcallrefs == 0)
1136 		wakeup(&cs->cs_upcallrefs);
1137 	return (SU_OK);
1138 }
1139 
1140 /*
1141  * Wait for all upcalls in progress to complete.
1142  */
1143 static void
1144 clnt_dg_upcallsdone(struct socket *so, struct cu_socket *cs)
1145 {
1146 
1147 	SOCKBUF_LOCK_ASSERT(&so->so_rcv);
1148 
1149 	while (cs->cs_upcallrefs > 0)
1150 		(void) msleep(&cs->cs_upcallrefs, SOCKBUF_MTX(&so->so_rcv), 0,
1151 		    "rpcdgup", 0);
1152 }
1153